2. What Are Bugs For?

What’s the most populace component of the human body? Cells? No. Genes? Not even close. It’s bugs. The microbes, including bacteria, that live in, on and around us outnumber our human cells 10 to 1. And researchers have just completed the first phase of the Human Microbiome Project, the most comprehensive accounting to date of who these microbial residents are and what they do. Most of them are actually our friends, working hard to ensure that we digest our food, for example, and build up strong immune systems. But as they learn more about the bugs that live within us, scientists are recognizing that they may play an important role in a number of chronic diseases and conditions, including inflammation and obesity. Far from being unwelcome intruders, these microbes may eventually help us treat some of our most intractable health problems.